Update documentation for outline-minor-mode.

README.org

@@ -18,12 +18,17 @@ as syntax highlighting to be performed more accurately than historical
 methods (e.g., regular expressions).
 
 This major mode provides support for syntax highlighting, indentation,
-navigation, Imenu, and "which function" (i.e., displaying the current
-function name in the mode line).
+navigation, Imenu, "which function" (i.e., displaying the current
+function name in the mode line) and outlining (via
+=outline-minor-mode=).
 
-*Note*: This major mode is based on the Emacs built-in tree-sitter
-support, not to be confused with the separate Emacs tree-sitter
-package.  The two are not compatible with each other.
+*Note*: This major mode is based on the Emacs 29 (or newer) built-in
+tree-sitter support, not to be confused with the separate Emacs
+tree-sitter package.  The two are not compatible with each other.
+
+*Note*: Outlining is made available through Emacs 30 (or newer) built-in
+support for outlining within tree-sitter major modes, therefore it is
+required for =outline-minor-mode= to work with =gpr-ts-mode=.
 
 * Prerequisites
 

doc/gpr-ts-mode.texi

@@ -29,12 +29,17 @@ as syntax highlighting to be performed more accurately than historical
 methods (e.g., regular expressions).
 
 This major mode provides support for syntax highlighting, indentation,
-navigation, Imenu, and ``which function'' (i.e., displaying the current
-function name in the mode line).
+navigation, Imenu, ``which function'' (i.e., displaying the current
+function name in the mode line) and outlining (via
+@samp{outline-minor-mode}).
 
-@strong{Note}: This major mode is based on the Emacs built-in tree-sitter
-support, not to be confused with the separate Emacs tree-sitter
-package.  The two are not compatible with each other.
+@strong{Note}: This major mode is based on the Emacs 29 (or newer) built-in
+tree-sitter support, not to be confused with the separate Emacs
+tree-sitter package.  The two are not compatible with each other.
+
+@strong{Note}: Outlining is made available through Emacs 30 (or newer) built-in
+support for outlining within tree-sitter major modes, therefore it is
+required for @samp{outline-minor-mode} to work with @samp{gpr-ts-mode}.
 
 @end ifnottex